Selector-stepper switch



Sept. 6, 1949. M. G. NELSEN SELECTOR-STEPPER SWITCH 3 Sheets-Sheet 2 Filed April 17, 1944 v*ZZ/n' for.' Mara?? (11d/ Z5 en sept 5, 1949. M. G. NELSEN SELECTOR-STEPPER SWITCH 3 Sheets-Sheet 3 Filed April 1'7, 1944 Patented Sept. 6, 194g UNITED STATES PATENT OFFICE SELECTOR-STEPPER SWITCH Marvin G. Nelsen, Skokie, Ill., assignor to Guardian Electric Manufacturing Co., Chicago, Ill., a corporationv of Illinois Application April 17, 1944, Serial No. 531,431

l 16 Claims;

This invention relates to selectcrstepper switch devices for controlling' the make and breaky .of portions ofy a plurality of different electrical circuits or branches of a main circuit. While for convenience reference will hereinafter be made in both the description and claims to a. plurality of branch circuits, it is to be understood that such terminology shall be construed to mean either branch or independent circuits, Switch devices of this general class are adapted to a relatively wide iield of use for direct or remote control of the operation of various types of devices or apparatus.

One ofl the objects of this invention is to provide a novel se1ector-stepper switch of the character indicated which is of simple, durable, compact construction, and which is positive in operation and capable of withstanding substantial vshoclr and vibration without being inadvertently actuated.

Another object is to provide a novel selectorstepp switch of the character indicated, provided with manually adjustable means which permits the switch to function automatically t0 complete temporarily, in rapid sequence, portions of a plurality ofdiiierent branch electrical circuits, or to cause selective and individual completion ofV one or more predetermined branch circuits.

A further object is to provideV an improved selector-stepper switch, characterized by the provision of novel means for producing pulsating operation of electro-magnet means i'or actuating the selector switch in a stepby'step manner.

Still another object is to provide an improved selector-stepper switch, characterized by the provision of a pair oi'opnositely arranged electromagnets, having their armatures connected together and pivoted on a common axis sc as to permit obtaining maximum power of the armature movement for actuating a ratcheting mechanism, and wherein the armatures provide counter balancing for precluding lfaulty or inadvertent actuation of the ratcheting means due to shock orvibration.

A still further object is to provide an improved selector-stepper switch, characterized by the provision of means for visually indicating the position of adjustment of the switch, and/or to designate a particular branch circuit to be completed.

Other objects and advantages of this invention will be apparent from the following description, taken in connection with the accompanying drawings, in which:

Figure 1 is a front elevational view of the switch device embodying the present invention.

Figure 2 is a vertical sectional View through the rear of the switch device, taken substantially as indicated at line 2--2'01/1 Figure 3,

Figure 3 isa staggered, vertical ectional View through therswitch device, taken substantially as indicated at line 3 3' on FigLu-'e 4.

Figure 4 is a vertical sectional view through the switch device, taken substantially as indicated at line @-4 on Figure 3.

igure 5 is a staggered, h rizontal sectional view through the switch device, taken substan tally as indicated at line 5-5 on Figure fl.

Figure 6 is a sectional view showing the contact panel and contact arm, taken substantially as indicated at line -G on Figure S.

Figure 'Z is a wiring diagram of the electrical circuits of the switch per se.

The selector-stepper switch embodying the present invention is a unitary assembly, including a main mounting panel l5 to which the various parts of the switch mechanism are attached. The switch mechanism is adapted to be housed within a rectangular sheet metal box I I, with the panel le seated against mounting brackets V2, to which the panel Ii is attached by means of screws lll. Connected tothe inner surface of the mounting panel Iii, is a frame l5, in the form .of a sheet metal stamping. Mounted in the rear wall of the frame l5, isl a bushing Iii, in which is journalled a shaft Ii'. Rigidly attached to the rear end of the shaft, protruding beyond the rearward wall of the frame i5, is a contacter arm; I8 of insulating material, on the outer end of which is mounted a contacter 2t, including a pair ofV spaced apart contact fingers El and The finger 2l is positioned to engage a circularly arranged series of spaced apart contact buttons '23, mounted on a panel 2li of insulating material, andY it may be understood that certain or" the contacts are connected to conductor wires oi separate, branch electrical circuits. The other contact ringer 22 engages a contact ring also mounted on the insulating panel in sturounding, spaced apart relation to the shaft l, as seen in Figure 6 oi the drawings. rlhus the fingers 2| and 22 serve to complete electrical branch circuits between the respective contact buttons 23 and the contact ring 25.

The contact buttons 23 are connected to terminals 21 carried on the opposite side of the panel 24, and the terminals are adapted to be connected by conductor wires into the various branch or separa-te main electrical circuits to 'be controlled. As will presently be described, mechanism is provided for rotating the shaft I1 in a step-by-step manner so that the finger 2I of the contact arm movesrin a. step-by-step fashion to engage successively the series of contact buttons 23. The insulating panel 24 is mounted in fixed spaced apart relation to the rear wall of the frame member I5, as seen in Figures 3 and 5 of the drawings, by means of spacer studs 29.

Attached to the rear wall of the frame I5, at one edge, as may be seen in Figure 5 of the drawings, is an insulating panel 3| on which is mounted a fuse 32, to take care of possible overload of the circuits including the entire control switch.

Rigidly mounted on the shaft I1, within the frame I5, is a ratchet wheel 35, having a multiplicity of teeth spaced apart circumferentially by angular amounts corresponding to the angular spacing of the contact buttons 23. The ratchet wheel is adapted to be yieldingly retained in any position of rotative adjustment by detent means, comprising a rigid bar 31, extending parallel to the axis of the shaft I1, in close proximity to the periphery of the ratchet wheel 35, and having an aperture in which is freely movable a metal ball 38, adapted to engage and seat between adjacent teeth of the ratchet wheel. A spring linger 39 engages the top of the ball and urges the latter yieldingly into engagement with the teeth of the ratchet wheel. The bar 31 and the finger 39 project rearwardly through an opening 40 in the rear wall of the frame member and are bent at right angles for fastening by screws 4I to the rear side of the rear wall of the frame I5, as seen in Figure 3 of the drawings.

Mounted in the frame I5, on opposite sides of the shaft I1, as seen in Figure 4 of the drawings, are electro magnetic devices, arranged in opposed relation to each other. One of the magnets includes a coil 44 secured to the upper wall of the frame I5, and the other magnet includes a coil 45 secured to the lower wall of the frame I5. The corresponding operating ends of the coils are distime the armatures are attracted to their corresponding coils. It is to be understood that each time the armatures are attracted to their coils, the pawl 54 drives the ratchet wheel 35 rotatively 5 to the extent of a single tooth. Such movement posed in opposed relation to each other. Cooperating with said ends of the coils are armatures 46 and 41 which are connected together t0 constitute a single armature element 48, journalled on the bushing I6, adjacent the ratchet wheel. The two armatures and their connecting portions desirably are formed as a unitary stamping, and the armatures are so dimensioned and related to each other as to provide a counter-balancing action of one with respect to the other. The armature element 48, including both of the armatures and 41, is urged in a counter-clockwise direction, as seen in the drawings, by a coil spring 50, surrounding the bushing I6, with one end of the spring as indicated at 50a anchored in an aperture I5a in the rear wall of the frame I5, while the opposite end of the spring as indicated at o is seated in a notch in the armature element 48, adjacent the armature 41, as seen in Figure 4 of the drawings. It is to be understood that the coil spring is initially tensioned before connection to the armature element. The armature element is arrested or limited in its outward position of adjustment with respect to the coils 44 and 45 by a stop member 52 positioned to be engaged by the armature 41, said stop member being connected to the bottom of a snapaction switch assembly, indicated generally at 53, attached to the upper wall of the frame I5.

Pivotally mounted at 54a, on the lower portion of the armature element, is a pawl 54 for driving the ratchet wheel in a step-by-step fashion each of the ratchet wheel is imparted to the shaft I1 to effect corresponding rotative adjustment of the contactor arm I8, so as to dispose the contact linger 2l in engagement with the next adjacent contact button 23. The pawl 54 has a coil spring 55 wound around its pivot connection to yieldingly urge the pawl into engagement with the ratchet. One end of the spring is anchored around the adjacent edge of the armature element and the other end engages the tail end of the pawl, as clearly seen in Figure 4 of the drawings. Just prior to the armature element assuming the position seen in Figure 4 of the drawings, the tail end of the -pawl is caused to abut against a trip arm 51, secured to the bottom wall of the frame I5, to shift the operating end of the pawl out of engagement with the teeth of the ratchet wheel.

In order to position the ratcheting mechanism and the contactor arm I8 at an initial or zero starting position, I provide a stop pin '6D on the forward face of the ratcheting wheel 35, positioned so that when the ratchet wheel is rotated it will engage a finger 6I, of a bracket member 62, which in turn is mounted on the inner face of the rear wall of the frame I5. Thus if a ratcheting mechanism is operated through its entire range of movement, or in the event it is disposed at some intermediate position and it is desired to reset the ratcheting mechanism,

35 together with the contactor arm to a zero or starting position, the shaft I1 is rotated in a counter clockwise direction until the pin 6i) engages the stop finger 6I. Such adjustment is permissible at all times when the electro-magnets are not being actuated.

The snap-action switch 53 is of the single pole double throw type and includes two iiXed contact lingers 64 and 65, and a movable contact finger 66. The movable contact linger is inter- 45 connected by a spring toggle 61 with an actuating arm S8 which is normally biased in a downward direction so that the movable contact linger 56 is in engagement with the fixed contact finger 64. Mounted on the under side of the outer end of the actuator 58 is a roller 59 yieldingly urged into contact with a cam member 1U, rigidly attached to the upper portion of the armature element 48. As the armature element rotates in clockwise direction, incident to 55 energization of the electro-magnets, the cam it acting on the roller 59 causes the actuator 58 to operate the snap-action switch so as to separate the movable contact iinger 55 from the fixed contact finger 64, and effecting engagement of 60 said movable finger 55 with the stationary finger 65. It is to be understood that the switch is actuated just prior to seating of the armatures on the ends of their respective coils, and to insure proper adjustment for such action, l provide an adjusting screw 12, engaging the fixed finger S4,

so as to move it upwardly or downwardly a relatively small amount to obtain the desired nicety of adjustment. It is also to be understood that the relationship of the switch to the cam is such as to permit the switch to reassume the vention is adapted to be operated by direct current. In order to obtain a stepping action by the electro magnets it is necessary that the magnets operate in an intermittent or pulsating manner. This intermittent or pulsating action is accomplished by means of the snap-action switch 53. However in order to insure the maintenance of the branch. circuit or circuits for a period of time surlicient to effect operation of the apparatus or devices being controlled thereby, there must be employed some form ofV time delaying means. For this purpose the electro magnet including the coil 44v is provided with a copper slug 44a, which functions in -a well understood manner, to eiect a delaying action in the release of the armatures after they have been attracted by energization of the coils;

Connected to the contact panel. 24 and positioned in close proximity to the coilv 44 is a condenser 15, which it may be understood is connected across the contact flngers 54 and 66 of the switch for suppressing arcingl of the switch.

lMounted on the forward .portion of the shaft I1, adjacent the inner wall of the main mounting panel l is a circular disc `80V attached to a hub 8l, which in turn is rigidly connected to said shaft by a set screw. The forward face of the disc is provided with a circumferentially arranged series of numbers, as indicated V82, which are spaced apart angular amounts corresponding to the spacing of the teeth of the ratchet wheel and the angular spacing ofthe contacts 23 on the contact panel. The numbers of the disc Bf!` are located so as to be sequentially registered with a window opening 83, in the main mounting panel I 0., as seen in Figure 1 ofthe drawings. When the mechanism is in its zero or starting` position, with the pin 60 of the ratchet wheel engaging the stop member 6|, the disc 80 is in position so that number 1 is disposed in registration with the window 83 as seen in Figure 1 of the drawings. As the ratchet wheel is operated in step-by-step manner to cause the contact arm to sequentially engage the series of contact buttons 23, the disc 3l)A is correspondingly rotated step-by-step so as to bring into corresponding registration with the window 83 the numerals corresponding with the respective contact buttons. In vother words, the numerals of the disc 8U-, visually indicate the particular main or branchr electrical circuit to be completed through the contactor arm. While in the construction illustrated., the number of the disc seen through the window 83 of the main panel I0 designates the circuit to be completed, if desired the construction may be modied so that the numeral would designate the kcirc-uit previously completed.

.The extreme end of the shaft I1 projects through the main `panel Iii and has rigidly attached thereto a knob 85, which for convenience, isv termed a reset knob. This knob may be manually engaged and rotated s o as to rea'dlust the ratcheting mechanism, as Well as the contactor arm I8, either to a zero starting position, or to any intermediate position. For example., if it is desired, under one condition of operation of the selector-switch, to com-plete only a single branch electrical circuit, such as designated by the numeral on the disc 80, the reset knob is rotated in the proper direction so` that said numeral is disposed in registration with the window 83.

Mounted on the main panel IB above. 'the ratche'ting mechanism is la tap swtchlll, :hav-

6 ing an operating shaft projecting through the panel and on the end of which is mounted a finger knob 9|. The iinger knob includes a pointer 92, and the knob is adapted to be rotated so as to dispose the tap switch in either of three positions of adjustment. In the position seen in Figure 1 of the drawings, the adjustment is such that the tap switch is in the Off position. When the switch finger 9| is rotated to the position indicated by the word single, the switch theny becomes adjusted so as to permit completion of only an individual branch electrical circuit and which circuit may be predetermined by adjustment of the reset knob 85 as above stated.

- When the nnger knob 9i is adjusted to the position indicated by the word Auto, the tap switch then is in a position of adjustment so that the ratcheting mechanism may be operated automatically to complete in rapid sequence a portion or the entire series of branch electrical circuits, by the pulsating actuation of the electro magnets. If the switch is to be operated automatically, the ratcheting mechanism is rst set at the zero or a desired starting position, and the tap switch correspondingly adjusted, then the automatic operation will take place and the entire series of branch circuits will be temporarily completed in sequence.

' To facilitate a clear understanding of the construction and operation of the switch embodying the present invention, reference will be made to the wiring diagram illustrated in Figure 7 of the drawings. The diagram merely represents the circuits of the selector-stepper switch per se, and it is to be understood that external auxiliary switch means, (not shown) is provided for controlling the actuation of the selector-stepper switch. Each time that the auxiliary control switch is closed the coils 44 and 45 are energized and attract the armatures to said coils, thereby actuating the ratchet wheel and contact arm I8 in a step-by-step manner and the snap switch 53, which is normally closed, and in series with the coils 44 and 45, is actuated during each attraction of the armatures to open the circuit including the coils 44 and 45, and simultaneously and temporarily completes the branch circuit through the contactor arm to the particular contact button 23 engaged by the contacter arm, for operating the apparaus controlled by the circuit. The copper slug 44a associated with the coil 44' serves to hold the armature element in attracted position for a relatively short interval of time so as to prevent instantaneous release of the armature element under influence oi the coil spring 50. The timing interval need only be a small fraction of a second, and for practical purposes 1t has been found satisfactory to utilize a copper slug which will permit the switch to operate, for automatically completing in sequence a series of branch circuits, at a speed at which the magnets are energized about ten times per second. When the armature element moves to its open position, the snap switch is actuated to again open the circuit to the contacter arm, and reestablish the circuit including the coils 44 and 45, so that the operation may be repeated. During such stepping movement, the indicating disc is simultaneously stepped to indicate the position of adjustment of the switch after completion of each or the entire series of stepping actions. The stop pin 60 eventually contacts the underside of bracket 62 if the auxiliary switch remains closed and prevents further operation of `armature 48. After actuation the selector switch may be manually reset by turning the knob 85 as above stated.

The operation above described corresponds to the adjustment of the nger piece 9| to the automatic position, as indicated in Figure 1 of the drawings, in which position current flows through the conductor wire DI to the tap switch, into the conductor wire |02, through the tap switch iinger |63, to the contact |04, and thence through conductor wire |65, and the movable switch finger 66, of the snap-action switch, to the switch nger 64, through the coils 44 and 45 of the magnets to ground. Thus the coils of the magnets are energized, and by the stepping action above described the snap switch is operated so that the movable switch finger 66 breaks contact with the switch finger 64, and completes contact with switch iinger 65, thus breaking the circuit including the coils 44 and 45, and completing the circuit through conductor wire |06, to the contactor arm I8, and the aligned contact button 23 to energize the particular branch circuit including the contact button engaged by the contactor arm I8. Due to the holding action of the copper slug 44a, the circuit through the contactor arm I8, and the registered contact button 23, is maintained for a short interval of time, after which the coils 44 and 45 release the armature element, and cause actuation of the snap-action switch to reestablish contact between the switch fingers 66 and 64, immediately after breaking contact between switch fingers 66 and 65. It will be apparent that the stepping action may be repeated, in a cyclic manner, and by virtue of which the ratcheting mechanism functions to complete in a rapid sequence the several branch circuits, including the respective contact buttons 23.

Now when the finger knob 9| is adjusted to the position indicated at single, only an individual i branch circuit may be completed when the auxiliary or control switch is operated. This branch circuit will include the contact button 23 engaged by the contactor arm I6, in a step position of adjustment. In other words, the reset knob 85 may be so adjusted for selecting any one of the entire group of branch circuits for completion. When the auxiliary or control switch is closed, current is permitted to iiow through :the conductor wire l i, through the tap switch iinger |01 and conductor wires |02 and |68. The conductor wire |68 merges with the conductor wire which controls the snap-action switch. Current also flows from the conductor wire |02 through the tap switch finger |03 through the conductor wire |69 into the coils 44 and 45 for energizing the same. Because current iiows through the path of least resistance, it will cause the electro magnets to be operated prior to the passage of Vcurrent through the snap-action switch and the contactor arm and hence the snap-action switch will become actuated, incident to'energization of the magnets, and current is then caused to flow through the movable switch finger 66, stationary iinger 65, through the conductor wire |66 and the contactor arm I8 Yfor completing the selected branch circuit,

through the corresponding contact button engaged by the contactor arm. This individual selected circuit will remain in closed condition until the control or auxiliary switch is again opened.

For convenience in illustration, a group of the contact buttons 23 in the wiring diagram have been designated by the numerals 1 to 6 inclusive,

and their respective contact terminals have been correspondingly designated in Figures 2 and 6 of the drawings.

While I have illustrated and described a preferred embodiment of my invention, wherein I utilize a pair of electro magnets arranged with interconnected armatures so as to obtain a counter balanced relationship which permits obtaining a selector stepper device capable of withstanding substantial shock and vibration, such as for use in aircraft, it will be manifest that for certain other uses a single electromagnet might be employed, utilizing the other novel constructional yfeatures of my invention to substantial advantage. I do not, therefore, wish to be understood as limiting this invention to the precise embodiment herein disclosed, except as I may be so limited by the appended claims.

I claim as my invention:

1. A selector switch comprising a series of spaced apart contacts adapted to be connected in separate, branch electrical circuits, a mounting frame, aV rotatable shaft carried on the frame, a contactor arm mounted on and rotatable with said shaft, a ratchet wheel iixedly mounted on said shaft, an electromagnet comprising a coil ixedly mounted on the frame and a cooperating armature mounted for free rotation on said shaft, a driving pawl carried on the armature and positioned to engage the teeth of the ratchet, to rotate the latter in one direction, together with the shaft and contactor arm, a predetermined angular amount, each time the armature is actuated by its coil, whereby to shift the contactor arm in a step-by-step manner to sequentially engage the contacts of the series, a detent Ifor releasably retaining the ratchet wheel, shaft and contactor arm at each stepped position oi adjustment, spring means for yieldingly urging the armature away from the coil, a stop for limiting outward movement of the armature, means for shifting the pawl out of engagement with the ratchet wheel as the armature approaches said stop, a finger knob on said shaft for manually rotating the shaft, ratchet wheel and contactor arm to dispose the latter in engagement with a predetermined contact of the series, indicia means comprising an element rotatable with the shaft for designating a particular branch circuit in correspondence with the contactor arm in engagement with a contact of the series, and a snapaction switch connected in circuit with said contacts and controlled by the armature and adapted to be closed, when the armature moves to its coil, to complete a branch circuit including the contact engaged by the contactor arm, incident to such movement of the armature.

2. A selector switch comprising a series of spaced apart contacts adapted to be connected in separate, branch electrical circuits, a mounting frame, a rotatable shaft carried on the frame, a contactor arm mounted on and rotatable with said shaft, a ratchet wheel flxedly mounted on said shaft, an electromagnet comprising a coil lxedly mounted on the frame and a cooperating armature mounted for free rotation on said shaft, a driving pawl carried on the armature and positioned to engage the teeth of the ratchet, to rotate the latter in one direction together with the shaft and contactor arm, a predetermined angular amount, each time the armature is actuated by its coil, whereby to shift the contactor arm in a stepby-step manner to sequentially engage the contacts of the series, a detent for releasably retaining the ratchet wheel, shaft and contactor arm at eac-h stepped position of adjustment, and a double pole. snap-action switch including a set cf normally opencontacts adapted. to be connected' in. a branch circuit. including the. contacter arm and the contact of theseries.. engagedby said arm, a set of normally closed contacts circuit with the coil, and an operating arm positioned to be controlled by the armature, whereby said sets of. contacts are reversed incident to movement of the. armature tothe-coil to. complete the branch circuit including the contact of the series then engaged by the contacter` arm.`

3.` A selector switch comprising a series. of spaced apart contacts adapted to be connected in separate, branch electrical circuits, a mounting frame., a, rotatable shaft carried on the frame, a contacter arm mounted on and rotatable with said. shaft, a ratchet wheel fixedly mounted on said shaft, an electromegnet comprising a. coil fixedly mounted on the. frame and a cooperating armature mounted for free rotation on said shaft., Va driving pawl carried onv the armature. and positioned to engage the teeth of the ratchet, to rotate the'A latter in one direction, together with the shaft and contacter arm, a predetermined angular amount,c each time the armature is actuated by its coil, whereby to: shift the. contactor arm in a step-by-step manner to sequentially engage the; contacts of the series, a detent for releasab-ly retaining the ratchet wheel, shaft and contacter arm at each stepped position of adjustment, a double pole, snap-action switch. including a set of normally open contacts adapted to be connectedl in al branch circuit including the contacter arm and, the contact ofV the; series engaged by i said arm, a set of normally closed contacts in circuit with the-coil, and an operating arm positioned to becontrolled by the armature., -whereby said sets of contacts.. are-reversed incident to movement of the armature to the coil to complete' the. branch circuit` including the contact of the-series then engaged by the contactor arm and time delay means for maintaining the armature attracted to the coil for a short interval of time for maintaining said. last. mentioned branch circuit complete for a. period of time.

4. A selector switch comprising a series of spaced apart contacts adapted tolbe connected in separate, branch electrical circuits, a mounting frame, a rotatable. shaft carried on the frame, a contactor arm mounted on'. and rotatable with said. shaft, a ratchet wheel. flxedly mounted n said shaft, an electromagnet. comprising a coil xedly mounted on the frame andy a, cooperating armaturemounted. for freerotation on said shaft,

.a driving pawl carried on the armature and .positioned to. engage the teeth of the ratchet, to rotate .the latter in. one direction', together with the shaft and/contacter arm. a predetermined angular amount, each time: the. armature is. actuated by its coil, whereby to shift. the. contacter arm in a step-by-step. manner to sequentially engage. .the contacts. of ,the series, a. detent for releasably retaining the. ratchet wheel, shaft, and contacter arm' at each stepped position of adjustment, a.

double, pole snap-action switch. including a, set of normally open contacts adapted to, be. connected in a branch circuit including the conductor arm and the contact of the. series engaged by said arm. a. set of. normally closed contacts. inv circuit with the coil, ,and1 an operating arm positioned to bey controlled', by the armature, whereby said sets of, contacts are reversed incident to movement of the armature to the coil to complete the branch circuit including the contact. of the series.

then engaged by the. contactor arm, time delay means for maintaining the armature attracted to theA coil. for a, short interval of time for maintaining said last mentioned branch circuit complete for a period' of time, and a manually adjustable control', switch connected in circuit with said coil and snap Switch and adapted in one position of operative adjustment to effect a pulsing operation of the electro magnet for automatically completing in. rapid sequence the branch circuits including a group of the contacts of the series.

5. A. selector switch comprising a series of spaced apart contacts adapted to be connected in. separate, branch electrical circuits, a mounting frame, a rotatable shaft carried on the frame, a, contacto): arm mounted' on and rotatable with saidv shaft, a ratchet wheel fixedly mounted on said shaft, an el'ectromagnet comprising a coil fixedly mounted. on the frame. and a cooperating armature mounted for free rotation on said shaft, a driving pawl carried on the armature and positi'oned' to engage the teeth of the ratchet, to rotate the latter in one directiom together with the shaft and contacter arm, a predetermined angular amount, each time the armature is actuated by its coil, whereby to shift the contacter arm in a step-by-stepV manner to sequentially engage the contacts of the series, indicia means comprising an element rotatable with the shaft for designating a particular branch circuit in correand an operating arm positioned t0 be controlled by the armature, whereby said sets of contacts are s reversed incident to movement of the armature to the coil to complete the branch circuit including the contact. of the series then engaged by the contactor arm, time delay means for maintaining the amature attracted to the coil for a short interval. of time for maintaining said last mentioned branch circuit complete for a period o-f time. a manually adjustable control switch connected in circuit with said coil and snap switch and adapted in one position of operative adjustment to effect a pulsing operation of the electromagnet for automatically completing in rapid sequence the branch circuits. including a group of the contacts ofthe series, and adapted. in another position of adjustment for completing an individual branch circuit corresponding to the particular conta-ct of the series engaged by the contacter immediately after actuation of the magnet.

6. A selector switch comprising4 a series of spaced. apart contacts adapted to be connected in separate, branch electrical circuits, a mounting frame, a rotatable shaft carried on the frame, a contacter` arm mounted on and rotatable with said shaft, a ratchet wheel fixedly mounted on said' shaft, manual: means on said shaft to rotate said shaft, ratchet wheel, and contactor arm to dispose the latter in engagement with a predetermined contact of said series, a pair of electro- V magnets comprising coils xedly mounted on the frame andV disposed on opposite sides of the shaft with. their correspondingl operating ends disposed in opposed relation to, each. other, and armatures for said coils arrangedL at opposite sides of the shaft, said armatures being connected together and mountedfor free. rotation on the shaft, and a driving pawI carried' on the armatures and poacerbes 11 Y sitioned to engage the teeth of the ratchet, to rotate the latter in one direction, togetherwith the shaft and contactor arm, a predetermined angular amount each time the armatures are actuated by their coils,rwhereby to shift the contactor arm in a step-by-step manner to sequentially engage the contacts of the series.

7. A selector switch comprising a series of spaced apart contacts adapted to be connected in separate, branch electrical circuits, a mounting -frame, a rotatable shaft carried on the frame, a contactor arm mounted on and rotatable with said shaft, a ratchet wheel xedly mounted on said shaft, a pair ofelectromagnets comprising coils xedlyrmounted on the frame and disposed on opposite sides of the shaft with their correspending operating ends disposed in opposed relation to each other, and armatures for said coils Y arranged at opposite sides of the shaft, said armatures being connected together and mounted for free rotation on the shaft, a driving pawl carried on the armatures and positioned to engage the teeth of the ratchet, to rotate the latter in one direction, together with the shaft and contactor arm, a predetermined angular amount, each time the armatures are actuated by their coils, whereby to shift the contactor arm in a step-by-step manner to sequentially engage the contacts of the series, a detent for releasably retaining the ratchet wheel, shaft and contactor arm at each stepped position of adjustment, spring means for yieldingly urging thearmatures away from their coils, a stop for limiting outward movement of the armatures, means for shifting the pawl out of engagement with the ratchet wheel as the armatures approach said stop, and a linger knob on said shaft for manually rotating the shaft, ratchet wheel and contactor arm to dispose the latter in engagement with a predetermined contact of the series.

8. A selector switch comprising a ,series of spaced apart contacts adapted to be connected in separate, branch electrical circuits, a mounting frame, a rotatable shaft carried onthe frame, a contactor arm mounted on and rotatable with said shaft, a ratchet wheel fiXedly mounted on said shaft, manual means on said shaft to rotate said shaft, ratchet wheel, and contactor arm to dispose the latter in engagementwith a predetermined contact of said series, a pair of electromagnets comprising coils fixedly mounted on the frame and disposed onv opposite sides of the shaft with their corresponding operating ends disposed in opposite relation to each other, and armatures for said coils arranged at opposite sides of the shaft, said armatures being connected together and mounted for free rotation on the shaft, a driving pawl carried on the armatures and positioned to engage the teeth of the ratchet, rto rotate the latter in one direction, together with the shaft and contactor arm, a predetermined angular amount, each time the armatures are actuated by their coils, whereby to shift the contactor arm in a step-by-step manner to sequentially engage the contacts of the series, and indicia means comprising an element rotatable with the shaft for designating a particular branch circuit in correspondence with the contactor arm in engagement with a contact of the series.

9. A selector switch comprising a series of spaced apart contacts adapted to be connected in separate, branch electrical circuits, a mounting frame, a rotatable shaft carried on the frame,

` a contactor arm mounted on and rotatable'with said shaft, a ratchet Wheel flxedly mounted on said shaft, a pair of electromagnets comprising coils fxedly mounted on the frame and disposed on opposite sides of the shaft with their corresponding operating ends disposed in opposed relation to each other, and armatures for said coils arranged at opposite sides of the shaft, said armatures being connected together and mounted for free rotation on the shaft, a driving pawl carried on the armatures and positioned to engage the teeth of the ratchet, to rotate the latter in one direction, together with the shaft and contactor arm, a predetermined angular amount, each time the armatures are actuated by their coils, whereby to shift the contactor arm in a stepM by-step manner to sequentially engage the contacts of the series, a detent for releasably retaine ing the ratchet Wheel, shaft and contactor arm at each stepped position of adjustment, spring means for yieldingly urging the armatures away from their coils, a stop for limiting outward movement of the armatures, means for shifting the pawl out of engagement with the ratchet wheel as the armatures approach said stop, a nger knob on said shaft for manually rotating the shaft, ratchet wheel and contactor arm to dispose the latter in engagement with a predetermined contact of the series, and indicia means comprising an element rotatable with the shaft for designing a particular branch circuit in correspondence with the contactor arm in engagement with a contact of the series.

10. A selector switch comprising a series of spaced apart contacts adapted to be connected in separate, branch electrical circuits, a mounting frame, a rotatable shaft carried on the frame, a contactor arm mounted on and rotatable with said shaft, a ratchet wheel flxedly mounted on said shaft, a pair of electromagnets comprising coils xedly mounted on the frame and disposed on opposite sides of the shaft with their corresponding operating ends disposed in opposed relation to each other, and armatures for said coils varranged at opposite sides of the shaft, said armatures being connected together and mounted for free rotation on the shaft, a driving pawl car- 4ried on the armatures and positioned to engage ward movement of the armatures, means for shifting the pawl out of engagement with the ratchet wheel as the armatures approach said stop, a finger knob on said shaft for manually rotating the shaft, ratchet wheel and contactor arm to dispose the latter in engagement with a lpredetermined contact of the series, indicia means comprising an element rotatable with the shaft for designating a particular branch circuit in correspondence with the contactor arm in engagement with a contact of the series, and a snapaction switch connected in circuit with said contacts and controlled by the armatures and adapted to be closed, when the armatures move to their coils, to complete a branch circuit including the contact engaged by the contactor arm, incident to such movement of the armatures.

11. AY selector switch comprising a series of 13 spaced apart contacts adapted to be connected in separate, branch electrical circuits, a mounting frame, a rotatable shaft carried on the frame,

a contacter arm mounted on and rotatable with said shaft, a ratchet Vwheel nxedly mounted on said shaft, a pair of electromagnets comprising coils AIixedly mounted on the frame and disposed on opposite sides of the shaft with their corresponding operating ends disposed in opposed relation to each other, and armatures'for said coils arranged at opposite sides of the shaft, said armatures being connected together 'and mounted for free rotation on the shaft, adriving Apawl carried on the armatures and positioned to engage the teeth of the ratchet, to rotate the latter lin one direction, together with the shaft and contacter arm, a predetermined angular amount, each time the armatures are actuated by their coil's,'whereby "to shift the contacter arm in a step-by-step manner to sequentially engage the contacts of Vthe series, a detent for releasably retaining the ratchet wheel, shaft and contactor arm at each 'stepped position of adjustment, land a ldouble to be controlled by the armatures, whereby .said

sets of contacts are reversed incident to movement of the armatures to their coils to complete the branch ycircuit including the contact of the series then engaged by the contacter arm.

12. A selector switch comprising a series of spaced apart contacts adapted to be connected in separate, branch electrical circuits, a mounting frame, a rotatable shaft carried on the frame, a contacter arm mounted on and rotatable with said shaft, a ratchet wheel fixedly mounted on said shaft, a pair of electromagnets comprising -coils xedly mounted on the frame and disposed on opposite sides of the shaft with their corresponding operating ends disposed in opposed relation to each other, and armatures for said `coils arranged at opposite sides of the shaft, said 'armatures being connected together and mounted for free rot-ation on the shaft, a driving pawl carried on the armatures and positioned to enf'gage the teeth of the ratchet, to rotate Ythe latter in one direction, together with the-shaft and contacter arm, a vpredetermined angular amount, `each time'the armatures are actuated by their coils, whereby to shift the contacter arm in a step-by-step manner to sequentially engage the contacts of the series, a detent for releasably retaining the ratchet wheel, shaft and Ycontactor arm at each stepped position of adjustment, a double pole snap-action switch including a set of normally open contacts adapted to be connected in a branch circuit including the contactor arm and the contact of the series engaged by said arm, a set of normally closed contacts in circuit with the coils, and an operating arm positioned to be controlled by the armatures, whereby said sets of contacts are reversed incident to movement of the armatures to their coils to complete the branch circuit including the contact of the series then engaged by the contacter arm, and time delay means for maintaining the armatures attracted to their coils for a short interval of time for maintaining said last mentioned branch circuit complete for a period of time.

13. A selector switch comprising a series of spaced apart contacts adapted to be connected in separate, branch electrical circuits, a mounting'frame, a rotatable shaft carried on the frame, a contactor arm mounted. on and rotatable with said shaft, a ratchet wheel riixedly mounted on said shaft, a pair of electromagnets comprising coils xedly mounted on the frame and disposed on opposite sides of the shaft with their corresponding operating ends disposed in opposed relation to each other, and armatures for said coils arranged at opposite sides of the shaft, said armatures being connected together and mounted for free rotation on the shaft, a driving pawl carried on the armatures and positioned to engage the teeth of the ratchet, to rotate the latter in one direction, together with the shaft and contactor arm, a predetermined angular amount. each time the armatiues are actuated by their coils, whereby t0 shift the contacter arm in a step-by-step manner to sequentially engage the contacts of the series, ya detent for releasably retaining the ratchet wheel, shaft and contacter arm at cach stepped position of adjustment, a double pole snap-action switch including a set of normally open contacts adapted to be connected in a branch circuit including the contactor arm and the yContact of the series enn gaged by said arm, a set of normally closed contacts in circuit with the coils, and an operating arm positioned to be controlled by the armatures, whereby said sets of contacts are reversed incident to inc-vement of the armatures to their coils to complete the branch circuit including the contact of the series then engaged by the contactor arm, time delay means for maintaining the armatures attracted to their coils for a short interval of time for maintaining said. last mentioned branch circuit complete for a period of time, and a `manually adjustable control switch connected in circuit with said coils and snap switch and adapted in one position of operative ladjustment to effect a pulsing operation of the electromagnets for automatically completing in rapid sequence the branch circuits including a group'of the contacts o1 the series.

14. A selector switch comprising a series of vspaced apart contacts adapted to be connected in separate, branch electrical circuits, a mounting frame, a rotatable shaft carried on the frame, a contactor arm mounted on and rotatable with said shaft, a ratchet wheel xedly mounted on said shaft, a pair of electromagnets comprising coils iixedly mounted on the frame and disposed on opposite -sides of the sha-ft with their corresponding operating ends disposcd in opposed relation to cach other, and armatures for said coils arranged at opposite sides of the shaft, said armatures being connected together and mounted for free rotation on the shaft, a driving pawl carried on the armatures and positioned to engage the teeth of the ratchet, to rotate the latter in one direction, together with the shaft and contacter arm, a predetermined angular amount, each time the armatures are actuated by their coils, whereby to shift the contactor arm in a step-by-step manner to sequentially engage the contacts of the series, indicia means comprising an element rotatable with the shaft for designating a particular branch circuit in correspondence with the contacter arm in engagement with a contact of the series, a double pole snap-action switch including a set of normally open contacts adapted to be connected in a branch circuit including the contactor arm and the contact of the series engaged by said arm, a set of normally closed contacts in circuit with the coils, and an operating arm positioned to be controlled by the armatures, whereby said sets of contacts are reversed incident to movement of the armatures to their coils to complete the branch circuit including the contact of the series then engaged by the contactor arm, time delay means for maintaining the armatures attracted to their coils for a short interval of time for maintaining said last mentioned branch circuit complete for a period of time, a manually adjustable control switch connected in circuit with said coils and snap switch and adapted in one position of operative adjustment to effect a' pulsing operation of the electro magnets for automatically completing in rapid sequence vthe branch circuits including a group of the contacts of the series, and adapted in another position of adjustment for completing an individualV branch circuit corresponding to the particular contact `of the series engaged by the contactor arm immediately after actuation of the magnets. y

15. A selector switch comprising a series of spaced apart contacts adapted to be connected in separate, branch electrical circuits, a mounting frame, a rotatable shaft carried on the frame, a contactor arm mounted on and rotatable with said shaft, a ratchet wheel flxedly mounted on said shaft, an electromagnet comprising a coil xedly mounted on the frame and a cooperating armature mounted for free rotation on said shaft, a driving paw] carried on the armature and positioned to engage the teeth of the ratchet, to rotate the latter in one direction, together with the shaft and contactor arm, a predetermined angular amount, each time the armature is actuated by its coil, whereby to shift the contactor arm in a step-by-step manner to sequentially engage the contacts of the series, and

a double pole snap-action switch including a set of normally open contacts adapted to be connected in a branch circuit including the contactor arm and the contact of the series engaged by said arm, a set of normally closed contacts in circuit with the coil, and an operating arm positioned to be controlled by the armature, whereby said sets of contacts are reversed incident to movement of the armature to the coil to Y complete the branch circuit including the con- 16 said shaft, an electromagnet comprising a coil xedly mounted on the frame and a cooperating armature mounted for free rotation on said shaft, a driving pawl carried on the armature and positioned to engage the teeth of the ratchet, to rotate the latter in one direction, together with the shaft and contactor arm, a predetermined angular amount, each time the armature is actuated by its coil, whereby to shift the contactor arm in a step-by-step manner to sequentially engage the contacts of the series, a double pole snap-action switch including a set of normally open contacts adapted to be connected in a branch circuit including the contactor arm and the contact of the series engaged by said arm, a set of normally closed contacts in circuit with the coil, and an operating arm positioned tobe controlled by the armature, whereby said sets of contacts are reversed incident to movement of the armature to the coil to complete the branch circuit including the contact of the series then engaged by the contactor arm, a manually adjustable control switch connected in circuit with said coil and snap switch and adapted in one position of operative adjustment to eiect a pulsing operation of the electro magnet for automatically completing in rapid sequence the branch circuits including a group of the contacts of the series, and adapted in another position of adjustment for completing an individual branch circuit corresponding to the particular contact of the series engaged by the contactor arm immediately after actuation of the magnet.

MARVIN G. NELSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 502,216 Wynne July 25, 1893 665,143 Stull Jan. 1, 1901 828,388 Cushman Aug. 14, 1906 830,209 Conkling et al. Sept. 4, 1905 1,126,084 Reisbach Jan. 26, 1915 1,438,947 Conway Dec. 19, 1922 1,506,580 Hallborg et al. Aug. 26, 1924 1,783,122 Horlacher Nov. 25, 1930 2,154,994 Prescott Apr. 18, 1939 2,324,474 Appel July 20, 1943 2,327,792 Hubbard Aug. 24, 1943 2,400,088 Hayslett et al May 14, 1946 FOREIGN PATENTS Number Country Date 406,111 Great Britain Feb. 22, 1934 

